Radio Morphing - towards a fast computation of the radio signal from air-showers

¹ Sorbonne Université, UPMC Univ. Paris 6 et CNRS, UMR 7095, Institut d’Astrophysique de Paris, 98 bis bd Arago, 75014 Paris, France
² LPNHE, CNRS-IN2P3 et Universités Paris VI & VII, 4 place Jussieu, 75252 Paris, France
³ Instituto de Física La Plata - CONICET/CCT- La Plata. Calle 49 esq 115 La Plata, Buenos Aires, Argentina
⁴ Vrije Universiteit Brussel, Physics Department, Pleinlaan 2, 1050 Brussels, Belgium
⁵ Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain
⁶ Clermont Université, Université Blaise Pascal, CNRS/IN2P3, Laboratoire de Physique Corpusculaire, BP.10448, 63000 Clermond-Ferrand, France

^★ e-mail: zilles@iap.fr

Published online: 24 September 2019

Abstract

Over the last decades, radio detection of air showers has been established as a promising detection technique for ultrahigh-energy cosmic rays and neutrinos. Very large or dense antenna arrays are necessary to be proficient at collecting information about these particles and understanding their properties accurately. The exploitation of such arrays requires to run massive air-shower simulations to evaluate the radio signal at each antenna position, taking into account features such as the ground topology. In order to reduce computational costs, we have developed a fast computation of the emitted radio signal on the basis of generic shower simulations, called Radio Morphing. The method consists in the calculation of the radio signal of any air-shower by i) a scaling of the electric-field amplitude of a reference air shower to the target shower, ii) an isometry on the simulated positions and iii) an interpolation of the radio pulse at the desired position. This technique enables one to gain many orders of magnitude in CPU time compared to a standard computation. In this contribution, we present this novel tool and explain its methodology. In particular, Radio Morphing will be a key element for the simulation chain of the Giant Radio Array for Neutrino Detection (GRAND) project, that aims at detecting ultra-high-energy neutrinos with an array of 200 000 radio antennas in mountainous regions.